Karl Warr’s incredible kiwi ingenuity is helping the environment and his small family fishing business. He has designed a filter that attaches to the end of a normal trawl fishing net that helps undersized and non-selected fish escape down on the bottom while the net is fishing. Releasing fish unharmed on the seafloor is very important to their survival chances.

Many of our inshore fish species have what are called swim bladders, these silky looking airbags inside the gut cavity of our fish, is what helps them control how they float in the water. They can inflate them with gases from the bloodstream so they can swim easily without fighting to either stay down or to stop them from sinking, but they can only do this very slowly. If fish are raised to the surface quickly this gas expands as the water pressure lessens the shallower you go.

The fish, unable to absorb all this expanded gas find that it stretches the sack containing it and starts squashing internal organs to the point of ruptures and beyond. Species like sharks and rays who have little or no swim bladders in most cases are fine, but our precious table fishes have significant trouble with this phenomenon. So what may look like a successful release from the surface could indeed be just the beginning of a long and painful death unless shortened by predators taking advantage of fish in trouble.

This filter looks rather like a large crayfish pot or cage in nature. Its shiny smooth stainless steel holes don’t flex and pinch fish as the net pulses along the bottom during fishing. The smoothness of the stainless steel rod construction allows even the most brazen escape to go off without a nasty carpet burn effect you get when fish struggle through woven netting.

Karl and his wife Sarah have been in the industry for over 20 years. During this time the economies of scale versus profitability have meant that small operations have become increasingly difficult to keep profitable. What might be little well known to many readers is that inshore fisher folk get paid quite meager amounts per kilo of whole fish landed. Currently it is common for fisher folk to earn around 2.50 a kilo for gurnard and around 1.50 per kilo for snapper to contract catch these fish for a quota holding factory. Larger operations therefore are more profitable due to sheer volume versus expenses, but it then becomes harder to find enough quota.

Straining every week to catch as much as possible to pay the bills, using old technology which is poor at releasing juvenile catches and by catch, meant Karl was not enjoying his work and becoming increasingly frustrated trying to make it all work.

The solution? For Karl and Sarah the solution was to introduce smarter gear and manage the sales of fish rite to the end user. The cage Karl uses is made from interchangeable panels that allow choices to be made as to what sized fish the net will then let go. These panels can contain hole shapes that conventional netting doesn’t allow for. For example when Karl is fishing for gurnard in an area where there may be trevally and snapper, a rectangular hole pattern is used so the round shaped gurnard of small size are released and at the same time the taller shaped small trevally and snapper can also be released. Previously with normal gear, letting small snapper and trevally go meant loosing most of the gurnard catch and vice versa equation meant killing lots of juvenile trevally and snapper to keep the gurnard catch up..

In Warr’s initial trial of the cage the release of juvenile gurnard was improved by 94%. Similarly on flounder big reductions in bycatch species and small sized flatfish were recorded.

This being said, better quality larger fish doesn’t make the finances balance if your still getting paid small amounts for your catch. "If you can’t catch enough fish to pay your bills, then you simply need to earn more from what you do catch". Karl does not consider it realistic to catch more from the environs where he fishes. "Being a boat that fishes in close well and truly amongst many other stakeholders, it’s imperative that I demonstrate best outcomes from what I do". To this end Karl and Sarah have taken to processing and marketing their catch in order to catch the full value of their fish.

"We don’t sell our fish for more than standard retail values, but we do deliver fish in a higher quality, environmentally more conscious and personal service fashion".

"Yes the middle sales people miss out in this model but for our local inshore fish stocks and stakeholder needs I feel the needs of the fish and the environment should be coming first".

When asked why more fishers are not using the cage method Warr replied "Each operation must weigh up its best set of approaches to the job", "the model I use relies upon capturing more value rather than simply capturing more fish"

Why I don’t choose more bulk volume is because I fish close and as such I don’t feel there is a future social appetite for one busy commercial fisherman versus many recreational and conservational minded voters experiencing maxed out harvesting consequences.

"A five year old boy who’s been sitting on the cold morning beach without a bite on the surf rod isn’t going to take any argument around CPU sediment or global warming"

"That kids just wanting to interact with his caregiver around the sea having fish in it". The skillset Sarah and I are using is also a bit of a barrier, not many fishers want to be processing fish after a hard week out catching it. Fishing folk may be shy or uncomfortable in so much marketing process, putting themselves out in the media spotlight and in front of the public. I know I certainly struggle at times with the privacy changes we have had to make.

Karl says that he is still working on developing an automatic cage with machine learning that will select each and every fish captured.

However because this project is above his resources they have partnered with Niwa and the University of Canterbury, plus a few international entities of significant experience.

The trial will demonstrate the release rates of juvenile snapper through the cage though.

Karl says that he’s been trying to encourage other fishing companies to take the cage on a couple of their boats. They say that they like idea but have not followed through.

They will certainly want the media kept out of it but they know I’m not ok with anything that’s hollow like that ‘Ocean Bounty’ stuff.

“It’s a weird place really - they can’t hate me but they also can’t invite me for a beer.”

I guess it really boils down to you New Zealand, how do you want your fish caught, where and what solutions can we as a nation come up with that honours all or as many as possible.

I certainly don’t see it as appropriate to tell any other fisher what should or should not be done. My wife and I are trying to respond to what we perceive as a wholesome way forward for our fishery, but at the end of the day we prefer those actions to be seen as an offering of options.

I believe that our best outcomes will evolve when industry is vigorously transparent, the public are well informed, policy makers are accurate and nimble, but most importantly when moral guardianship over the people’s commons is protected by independent and unbiased evidence based best practice.